Air extractor for vehicles or buildings



Sept. 1 1929- J. MUIRHEAD ETAL AIR EXTRACTOR FOR VEHICLES OR BUILDINGS Filed Oct. 26, 1928 fave/Mar:

Aft v,

Patented Sept. 10, 1929.

llhll'lEl) STATES JAMES MUIRHEAD AND DAVID PRAIN IVIUIBHEAD, OF GLASGOW- SCOTLAND.

AIR EXTRAC'I'OR FOR VEHICLES OR BUILDINGS.

Application filed October 26, 1928, serialNo. 315,264, and in Great Britain October 12, 1927.

This invention relates to an improved air extractor for extracting the vitiated air from the compartments of road or railway vehicles, but applicable also to buildings and other 5 structures, whether stationary or movable.

One of the objects of this invention is to design and construct an air extractor for the compartments of railway carriages, which shall comply with the present requirement ot railway authorities that any ventilating contrivance fitted to the roof of a railway carriage shall be devoid of any moving parts and capable of being made of cast metal.

A further object of the invention is to proride an air extractor which shall function with the entire absence of any down-draught, even when the railway carriage or vehicle is travelling at a high speed and irrespective of the direction of motion of the vehicle.

2 A still further object of our invention is to exclude any possibility of ashes, cinders or the like entering the compartment of the railway or other vehicle through the air extractor.

According to the present invention, the air extractor comprises a straight uptake or air shaft having two parallel sides across or at right angles to the direction of motion of the vehicle, a cowl or deflector of inverted substantially U-shape or having two oppositely inclined flat or slightly curved surfaces, one over each of said parallel sides, said inclined surfaces being connected by an intermediate flat or curved surface situated centrally over the air shaft, an air duct on the outside of each parallel side of the air shaft, said air ducts being open below and communicating over the sides of said air shaft with the space at the top thereof, and an air channel alongside of the lower open end of each air duct, said air channel being open above to the wind currents and being so designed that the outer walls of the air channel deflect the wind currents over the air duets.

The accompanying sheet of drawings illustrate an example of an air extractor constructed according to the present invention.

1 is a longitudinal sectional View and 2 a side view of the device. Fig. 3 is a plan view of the device surface 11 or the cowl may consist of a suit- In carrying out our invention as illustrated, the air extractor comprises a base plate 6 having an elongated oblong aperture to register with an aperture 5 in the roofof the compartment to be ventilated, a pair of spaced parallel upstanding side plates or flanges 13, a pair of parallel cross plates or members 7 ext iding across between said side plates, 13, one along each of the wider sides of said aperture, to forma rectangular air so shaft 10 surmounting said aperture 5, a cowl 11 siuhniounting said shaft 10 so that air passages 9 are formed over the wider sides of said shaft 10, and baffles ,8 extending downwards from said cowl 11, one alongside each of thewider sides of said air shaft 10 but spaced therefrom and terminating at a short distance from said base plate 6, in combination with a pair of deflectors 18 extending upwards from said base plate 6, one alongside of andspacedvat a distance from each battle 8 between said side plates 13. p

The air extractor may be cast as a single unit adapted 'to be secured to the roof of the compartment to be ventilated, The cowl as shown may consist of oppositely inclined surfaces 11, one over each of the wider sides of the air shaft, said inclined surfaces being connected by an intermediate flat or curved ably curved plate symmetrically located over the air shaft.v The baflies 8' which extend downwards from v the cowl may be either parallel with the Wider sides of the air shaft or divergent therefrom. The deflectors 18 located outside the baffles 8 are designed to deflect the wind currents over theair channel or space 20 between the baffle 8 and deflector 18. For this purpose, the deflector may be a plate inclined as shown or curved inwards towards its upper end, or having its outer surface so inclined or curved.

In order to drain the air channels or spaces 20 between thebafiles 8 and the deflectors 18 in the event of water collecting therein when the vehicle is stationary, suitable drainage may be provided. For this purpose, the base plate may be formed with a cambered surface or otherwise formedor adapted to discharge til the water towards holes 19 in one or both side plates 13.

Although our invention is especially suitable for manufacture in cast-iron or other cast metal, it may also be built up of sheet metal or other material as in the construction illustrated. a

The invention has been described herein more particularly in its application to moving vehicles, but it is also applicable to stationary structures such as buildings, in such case air extraction being dependent upon the wind Curr nts which pass over or across the roof of the buildin Claims:

1. An air extractor comprising in combina tion, a base having an elongated oblong aper ture therein, a pair of spaced parallel longitudinal members extending upwards from said base, a pair of parallel cross members extending upwards iErom the longer sides of said aperture between the longitudinal members and joined thereto, a cowl centrally disposed over the space betweensaid. cross members and extending to said longitudinal members, baflles extending downwards from said cowl alongside said cross members but spaced therefrom and terminating at a distance from the base and extending to said longitudinal members, and a pair of deflectors extending upwards from said base at a distance from each battle and inclined towards the cowl, and

. designed to deflect wind currents over the spaces between the bali'ies and deflectors.

. 2. An air extractor compr sing in comblnation, a base having an elongated oblong aperture therein, a pair of spacedparallel longitudinal members extending upwards from said base, a pair or parallel cross mem bers extending upwards from the longer sides or" said aperture between the longitudinal members and joined thereto, a cowl centrally disposed over; the space between said cross members and extending to said longitudinal members and comprising downwardly inclined sides extending over said parallel cross 'me'mbers, batlies extending downwards from said cowl alongside said cross members but spaced therefromand terminating at a dis-' tance from'the base "and extending to said longitudinal members, and a pair of deflectors extending upwards from said base at a distance from each baflle, and designed to deflect windicurren'ts overthespaces between the battles and deflectors;

3. 'An air extractor comprising inc'ombination, a base having an elongated oblong aperture therein, a pair of spaced parallel longitudinal members extending upwards from said base, a pair of parallel cross mem bers extending upwards fromthe longer sides oi said aperture between the longitudinal members and joined thereto, a cowl centrally I disposed over the space between said cross members and extending to said longitudinal members and comprising downwardly inclined sides extending over said parallel cross members, bafiies extending downwards from said cowl alongside said cross members but spaced therefrom and terminating at a distance from the base and extending to said longitudinal members, and a pair oi deflectors extending upwards from said base at a distance from each baflie and inclined towards the cowl, and designed to deflect wind currents over the spaces between the battles and deflectors.

The foregoing specification signed at Glasgow, Scotland, this twelfth day of October, 1928.

JAMES MUIRHEAD. DAVID PRAIN MUIRHEAD. 

